IMDs provide therapies to patients suffering from a variety of conditions. IMDs can be utilized in a variety of applications, such as drug or fluid delivery, monitors, and therapeutic devices for other areas of medicine, including metabolism, endocrinology, hematology, neurology, muscular disorders, gastroenterology, urology, ophthalmology, otolaryngology, orthopedics, and similar medical subspecialties. Many IMDs are designed to generate and deliver electrical pulses to stimulate body tissue, muscles, body fluid, etc.
Examples of IMDs involving cardiac devices are implantable pacemakers and implantable cardioverter-defibrillators (ICDs). Such cardiac IMDs typically monitor the electrical activity of the heart and may provide electrical stimulation to one or more of the heart chambers when necessary. For example, pacemakers are designed to sense arrhythmias, i.e., disturbances in heart rhythm, and, in turn, provide appropriate electrical stimulation pulses at a controlled rate to selected chambers of the heart in order to correct the arrhythmias and restore the proper heart rhythm.
ICDs also detect arrhythmias and provide appropriate electrical stimulation pulses to selected chambers of the heart to correct the abnormal heart rate. In contrast to pacemakers, however, an ICD can also provide pulses that are much stronger and less frequent, where such pulses are generally designed to correct fibrillation, which is a rapid, unsynchronized quivering of one or more heart chambers, and severe tachycardias, during which the heartbeats are very fast but coordinated. To correct such arrhythmias, ICDs deliver low, moderate, or high-energy therapy pulses to the heart.
FIG. 1 is an illustration of a prior art IMD 100 implanted in the body of a patient 102. FIG. 1 also depicts an external communication device (such as a programmer 104) that is not implanted within patient 102. Telemetry communications can take place between IMD 100 and programmer 104 using known wireless telemetry techniques and technologies. The arrows in FIG. 1 represent such telemetry communications. In practice, a given communication session between programmer 104 and IMD 100 may be unidirectional or, as illustrated, bidirectional.
Programmer 104 permits non-invasive communication with IMD 100, where such communication is enabled via downlink and uplink communication channels. Generally, any form of portable programmer, interrogator, recorder, monitor, or telemetered signals transmitter and/or receiver found suitable for communicating with IMD 100 could be used for programmer 104. Programming commands or patient data can be transmitted between one or more antennas of IMD 100 and one or more antennas of programmer 104.
When IMD 100 is used for cardiac applications (e.g., to provide cardiac sensing, pacing, and/or defibrillation functions for patient 102), IMD 100 can be a cardiac device—for example, a pacemaker, an ICD, a hemodynamic monitor, or the like. IMD 100 is implanted beneath the skin or muscle of patient 102. When IMD 100 is used for cardiac applications (as shown in FIG. 1), IMD 100 is electrically coupled to the heart 106 of the patient 102 through electrodes connected to one or more leads 108. The leads 108 are routed inside the heart 106 such that the electrodes can be attached within the heart 106 at the desired location. The leads 108 are typically coupled to a connector block 110 of IMD 100 in a manner well known in the art.
Various desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.